The dental restoration of a partially or wholly edentulous patient with artificial dentition is typically done in two stages. In the first stage, an incision is made through the gingiva to expose the underlying bone. After a series of drill bits creates an osteotomy in the bone, a dental implant is placed in the jawbone for integration. The dental implant generally includes a threaded bore to receive a retaining screw holding mating components therein. During the first stage, the gum tissue overlying the implant is sutured and heals as the osseointegration process continues.
Once the osseointegration process is complete, the second stage is initiated. Here, the gum tissue is re-opened to expose the end of the dental implant. A healing component or healing abutment is fastened to the exposed end of the dental implant to allow the gum tissue to heal there around. Preferably, the gum tissue heals such that the aperture that remains generally approximates the size and contour of the aperture that existed around the natural tooth that is being replaced. To accomplish this, the healing abutment attached to the exposed end of the dental implant has the same general contour as the gingival portion of the natural tooth being replaced.
During the typical second stage of dental restoration, the healing abutment is removed and an impression coping is fitted onto the exposed end of the implant. This allows an impression of the specific region of the patient's mouth to be taken so that an artificial tooth is accurately constructed. After these processes, a dental laboratory creates a prosthesis to be permanently secured to the dental implant from the impression that was made.
In addition to the more traditional system for placing dental implants described above, some systems use guided placement of the dental implants. In these situations, a surgical plan is developed for the patient that will include the location and orientation of the implants to be installed by a surgical guide. Once the surgical plan is known, the surgical guide can be developed and, eventually, placed in the patient's mouth at the known location. The surgical guide includes openings for providing the exact placement of the drill bits used to create the osteotomy. Once the osteotomy is completed, the surgical guide may permit the dental implant to be placed through the same opening and enter the osteotomy that was guided by the surgical guide.
Surgical guides can be created by the use of a CT-scan of the patient's mouth. The CT-scan provides enough detail to develop the surgical guide by use of various methods. For example, a CT-scan can provide the details of the patient's gum tissue and/or remaining teeth so that the surgical guide can be developed based on computer-aided design (CAD) and computer-aided manufacturing (CAM). One example of the use of a CT-scan is disclosed in U.S. Patent Publication No. 2006/0093988, which is herein incorporated by reference in its entirety. This publication also describes the use of various tubes that can be placed within the surgical guide to receive the drill bits and implants.
However, some problems may occur with the development and manufacturing of the surgical guide. For example, the surgical plan may require the use of a certain sized implant, dental drill, or other components that may not fit well in the patient's mouth due to the opposing (i.e., upper or lower) teeth and/or gum tissue in the patient's mouth. Thus, the clinician may be disappointed because of the considerable amount of time and effort in planning the case, only to need a revised plan and possibly a new surgical guide. The patient, of course, is also disappointed because he or she did not receive what was expected in that visit (possibly a temporary prosthesis) and will be forced to return an additional day to complete the project.
As such, a need exists to develop an improved CAD-CAM related methodology for developing a surgical plan and a surgical guide that is used in accordance with the surgical plan.